Electric signaling apparatus



(No Model.) 4 Sheets-Sheet 1. $.11. FIELD.

ELECTRIC SIGNALING APPARATUS.

Patented May 2,1893.

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. ELECTRIC SIGNALING APPARATUS. 'No. 496,602. Patented May 2, 1893.

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' Patented May 2, 1893.

(No Model.) 4 Sneets-Sheet .4. S. D. FIELD. ELECTRIC SIGNALING APPARATUS- No. 496,602. Patented May 2, 1893.

m m. Mi m w z a l M m UNITED STATES PATENT OFFICE.

STEPHEN DUDLEY FIELD, OF YONKERS, NEW YORK.

ELECTRIC SIGNALING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 496,602, dated May 2, 1893. Application filed January 23,1893. Serial No. 459,379. (No model.)

To on whom it may concern.-

Be it known that I, STEPHEN DUDLEY FIELD, acitizen of'the United States, residing at Yonkers, in the county of Westchester and State of New York, haveinvented certain new and useful Improvements in Electric Signaling Apparatus; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to electric signaling and is designed to facilitate transmission of intelligence by means of electrical vibrations or undulations. It is more particularly applicable to the transmission of such vibrations or undulations as are created by and similar in frequency and character to the air waves developed by the voice in speech, although some of the features are applicable to the transmission of telegraphic signals. One of the basic features of the invention involves the elimination of magnetic retardation such as arises from self-induction in ordinary electro-magnetic apparatus. Another feature involves the elimination of the mechanical retardation of action due to the inertia of the moving parts.

In carrying out my invention I support in a magnetic field a conductor in a condition of neutral stress, that is to say, in a condition in which the conductor will vibrate responsivcly to vibrations of any frequency or sound waves of any pitch or quality, and provide means by which such conductor may be thrown into vibration in accordance with the signals to be transmitted. I prefer to so arrange the conductor that the reaction of its several parts will assist the flow of current and in order to accomplish this result I form of it a single conductor or a multiple bifilar conductor which is stretched in an intense magnetic field so that when thrown into vibration its two sides moving in opposite directions will act cumulatively in generating current or responding thereto, and will mutually assist a flow of current. A diaphragm or similar device is connected with one end of the conductor by which it may be thrown into vibration or upon which it may act to produce -vibration.

My invention therefore comprises an electric conductor supported in a magnetic field in a state of stress and so arranged that it may be thrown into vibration in accordance with the signals to be-transmitted. It also comprises such a conductor mechanically connected with an elastic diaphragm by which it may be thrown into vibration or upon which it may reproduce vibrations. The condition of stress in the conductor may be maintained mechanically or electrically, and the field in which it vibrates may be bipolar or multipolar in character.

The several features of novelty will be more particularly hereinafter described and will be definitely indicated in the appended claims.

In the accompanying drawings which illustrate the invention, Figure 1 isa side elevation partly in section of an instrument constructed in accordance with my invention, the section being taken on a plane indicated by the line a y of Fig. 2 looking in the direction indicated by the arrow; the conductor in the apparatus illustrated in this figure is maintained in a condition of stress by mechanical means. Fig. 2 is a side elevation of the device shown in Fig. 1. Fig. 3 is a section partially in diagram of a modification in which the conductor is maintained in a condition of stress by electrical means. Fig. 4 is a view similar to Fig. 3 in which another method of producing the stress is illustrated. Fig. 5 is a similar View to Fig. 3 in which a multipolar field is used; and Fig. 6 is a partial plan of Fig. 5.

Referring to the drawings, A indicates a magnet which may be a permanent magnet preferably compound in character, as shown, or may be an electro-magnet provided with pole-pieces N, S between which is produced an intense magnetic field. Stretched across this magnetic field is an electric conductor B which may be a single conductor or may be composed of a loop or a series of loops as indicated. At one end the conductor or the loop into which it is formed is connected to adiaphram O and to the other endis connected an adjusting screw D by which the tension may be varied. The terminals of the conductor or loop are connected with two binding-posts which may run to line directly, or as indicated in Figs. 3, 4 and 5 may connect with the primary of an induction coil by which the tension of the generated currents may be raised. In the form shown in Fig. 2 at intermediate points, preferably the middle points, ot the conductor is connected an inharmo- IllOllS spring such as a sphere of rubber E by which it will be maintained in a normal condition of inharmonious stress. When a loop or bifilar conductor is used both sides will be connected to such an inharmonious spring as shown. It air waves are caused to impinge upon the diaphragm O the stretched conductor will be thrown into vibration in accordance with the characteristics of such air waves, or if the diaphragm is caused to vibrate by any other agency the conductor will act responsively to the vibrations. The movement of the conductor in the magnetic field causes it to out the lines of force of said field and develop an induced current which flows toline or theinduction coil above referred to. In the form illustrated the two sides of the loop will be caused to vibrate in opposite directions and will thus develop currents which will assist one another in their passage through the loop. In this respect it differs from ordinary generating coils. In the ordinary magneto telephone, for example, the diaphragm is inharmonious and will respond to air waves of any pitch or quality but the generating coil has high self-induction which confines its power within narrow limits. By forming a loop as shown in the drawings, however, the conductor is given a bifilar character so that the currents How in opposite directions in the two opposite sides and assist each other by mutual induction, thus counteracting the choking effect of self-induction and permitting the currents to flow with much greater freedom. By means of the system of suspension illustrated the conductor becomes an inharmonious vibrator which will respond to vibrations of any character produced in the diaphragm, and the conductor being normally in a condition of mechanical stress is ready to respond instantly to any vibration communicated to it.

In Fig. 3 the inharmonious springs E, E have been dispensed with and alocal battery F isplaced in circuit with the primary of an induction coil and the vibratory conductor, which causes the two sides of the conductor to diverge and be maintained in a condition of stress by mutual repulsion due to current circulating in opposite directions.

In Fig. 4 I have shown a weight G in lieu of the adjusting screw D for balancing the repulsive effect due to the battery and yieldingly maintaining the conductor in a condition of stress.

In ordertoincrease the electro-motive-force developed by the vibration of the conductor the field may be made multipolar in character, as indicated in Figs. 5 and 6, where the successive magnets present to the same side of the conductor alternately north and south poles. When the conductor is thrown into vibration its reaction upon the field will be somewhat as indicated by the dotted lines, the successive magnets forcing the conductor in opposite directions causing its vibration to assume a sinuous character.

The instrument herein described may be used either as a transmitter or a receiver. When acting as a receiver the current waves circulating over the conductor cause it to react on the magnetic field, and by such reaction to vary the strain on the diaphragm, reproducing in the air adjacent thereto sounds analogous to those developing the transmitting current impulses. The instrument may act purely as a magneto instrument, as illustrated in Fig. 1, in which case its terminals, whether acting as a transmitter or receiver, may be connected directly to line; or it may be assisted by a battery placed in series with the line, or may be included in alocal circuit containing a battery and including the primary of an induction coil. In some cases the transmitting outfit may be placed in series with the line and a battery of considerable power be put in shunt relation to both, a style of coupling so obvious that further description is deemed unneccessary.

An instrument of the kind herein described will act either as a receiver or transmitter in a circuit equipped with a complementary instrument of any other character; that is to say, an ordinary receiver would respond to impulses developed by my instrument acting as a transmitter or my instrument would act as a receiver with an ordinary transmitter. It will be noticed that in this apparatus the halting or mutilation of signals due to self-induction of the currents circulating in the various conductors is almost wholly eliminated. This is true even with theinduction coil in circuit. Thus the secondary coil surrounds the primary, the terminals of which are closed through the battery and inducing conductors, thereby becoming short circuited through a fixed or constant resistance, which resistance is so low as to practically short circuit the primary. It is well known in the art that a properly constructed induction coil loses its property of self-induction or drag when its primary is short circuited. The inducing circuit by reason of its bifilar composition is necessarily devoid of self-induction as hereinbefore explained. It should be noted that although the conductor and diaphragm are normally under strain or stress such stress is inharmonious. A diaphragm as is well known is responsive to vibrations of any character or is inharmonious, but an ordinary stretched string or Wire connected thereto would cause it to respond more readily to vibrations of a certain character. It is for the purpose of obviatin g such a result that I provide the inharmonious rubber springs E, E. The battery when put in circuit acts also to render the conductor, although stretched, inharmonious, in a manner not readily explained, but which may be by reason of exerting a constant flexin g pressure on the conductors putting a strain upon the wire without communicatingany' v fundamental rate to it; as the diaphragm moves the resulting motion of the conductor induces currents which add to or substract from the battery current in strict proportion to the degree of movement. This mode of rendering the stretched conductor inharmonious is distinctly different from the case of a tuned wire supported between two fixed points. In the latter case when we deflect the wire we meet uniform and increasing strain as the deflection becomes more and more pronounced, which is a necessary incident of the conductor sounding any definite musical note. If, however, we provide means for simultaneously releasing the strain as the conductor is deflected in exact proportion to the amount of deflection, we destroy its harmonic property and it ceases to vibrate to a fixed note or tone. In case the wire be deflected upward when the diaphragm is at rest further inward movement of the diaphragm will result in further upward movement of the wire. The counter-electro-motive-force set up by the vertical movement of the wire will be against the local current and tend to diminish its strain on the diaphragm. Thus practically all the work is thrown on the local battery and the diaphragm becomes simply a governing agent, which, when it recedes, pulls down the wire against the upward pressure given by the combined action of the battery and the magnetic field.

A distinctive feature of my invention lies in the fact that the system I employ enables me to useavery dense magnetic field,because the pole faces may be brought into very close juxtaposition as the generating conductor occupies very little space, so that a very short air gap is possible with aresultin g increase in the strength of the field. It will thus be seen that my apparatus meets all requirements of perfect transmission of speech, namely, neutrality of moving parts, absence of inertia, and elimination of self-induction, a combination which, so far as I am aware, is for the first time met. An effort has been heretofore made to generate currents by connecting a siphon recorder coil to a diaphragm, but the inertia of the parts and the self-induction of the coil were sufficient to render the apparatus inefficient. So in the ordinary carbon transmitter the variation of conductivity, which is the basic principle of operation, varies the self-inductive properties of the circuit within a considerable range, such selfinduction acting upon the induction coil, the

primarycircuit of which has a fluctuating resistance. In my case, however, the primary circuit of the induction coil has a constant resistance at all times and self-induction by reason of the closed circuit of practically constant low resistance is reduced to a minimum.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. A signaling instrument comprising a diaphragm or other neutral or inharmonious vibrating agent, and a neutral inharmoniousinductive circuit mechanically connected thereto. I

2. A signaling instrument for vibrating or undulating currents comprising a conductor supported in a magnetic field and mechanically connected with an inharmonious vibrator, the apparatus being normally in a state of stress.

3. A signaling instrument for vibratory or undulatory currents comprising a conductor supported in a magnetic field and mechanically connected to a diaphragm, both conductor and diaphragm being in a state of stress.

t. A signaling instrument for vibratory or undulatory currents comprising a conductor supported in a magnetic field so as to cut transversely the lines of force of said field, means for producing lateral stress on the conductor, and a diaphragm mechanically connected to the conductor.

5. A signaling instrument for vibratory or undulatory currents comprising a conductor supported in a magnetic field so as to out transversely the lines of force of said field, one end of said conductor being fixed to a tension regulating device, and the other end to a diaphragm, and auxiliary means for producing a lateral stress in the conductor.

6. A signaling instrument for vibratory or undulatory currents comprising a conductor supported in a magnetic field, means for maintaining the conductor in inharmonious lateral stress, and a diaphragm mechanically connected to the conductor.

'7. A signaling instrument for vibratory or undulatory currents comprising a conductor supported in a magnetic field so as to cut transversely the lines of force of said field, an inharmonious flexing device for bending the conductor in the field, and a vibratory me dium mechanically connected to the conductor.

8. A telephone system comprising a conductor supported .in a magnetic field so as to cut transversely the lines of force of said field, a diaphragm connected under tension with said conductor, an electric generator in circuit with the conductor, and a line opcratively related thereto.

9. A telephone system comprising parallel wires supported in a magnetic field so as to cut transversely the lines of force of said field, a diaphragm connected under tension to one end of the wires, an electric generator in circuit with the wire terminals, and a line operatively related to the generator and wires.

10. A telephone system comprising parallel conductors held in tension in a magnetic field, a diaphragm connected to said conductors so as to communicate vibrations thereto, a battery connected to the conductor terminals, an inductive transformer having its primary winding in circuit with the conductors, and a telephone line connected to its secondary winding.

11. A signaling instrument comprising a diaphragm and a bifilar inductive circuit operatively related thereto, the two sides of said bifilar circuit lying parallel to one another.

12. A signaling instrument comprising a bifilar inductive circuit, the two sides of which are relatively arranged so as to eliminate selfinduction, and means for vibrating said bifilar circuit in accordance with signals to be received or transmitted.

13. The combination of a bifilar conductor supported in a magnetic field of force, and a diaphragm mechanically connected to said conductor.

14. The combination of a bifilar conductor supported in a magnetic field, an induction coil in circuit therewith, and a diaphragm operatively connected to said conductor.

15. The combination of a bifilar conductor supported in a magnetic field,- a local circuit connected thereto including the primary circ'uit of an induction coil, and a diaphragm mechanically connected to said bifilar conductor.

16. A signaling instrument comprising a conductor supported transversely across the lines of force of a magnetic field, a diaphragm connected to said conductor, and means for STEPHEN DUDLEY FIELD.

Witnesses:

JAMES S. FITCH, OsoAR B. WARING. 

